Cardiovascular
Heart rate, VO2 max, and what the numbers on your wearable actually mean.
7 articles
Why Fever Makes You Shiver
You're running a fever and wrapped in a blanket shivering anyway — that's not a contradiction. Here's how your hypothalamus resets its own temperature target during illness, and why your body reacts as if it's suddenly cold.
Why Your Hands Go Cold But Your Core Stays Warm
Your fingers go numb long before your chest feels cold — and that's a deliberate trade your body makes, not a malfunction. Here's the vasoconstriction mechanism that decides who gets the warm blood first.
Why Standing Up Fast Makes You Dizzy
That head-rush moment when you jump up off the couch has a name — orthostatic hypotension. Here's the reflex that's supposed to catch the blood pressure drop, and why there's a brief lag before it does.
The Early Heart Attack Warning Signs Most People Ignore
Most heart attacks give a warning first — sometimes weeks first. Here's what the research actually shows about the early signs people dismiss, why chest discomfort gets mistaken for indigestion, and when to stop waiting and call for help.
What Actually Happens During a Heart Attack
It doesn't start with the chest pain. Here's the real timeline — plaque rupture, a clogging clot, the minutes-long clock on heart muscle damage, why pain shows up in the jaw or arm, and what aspirin and emergency treatment actually do.
The VO2 Max Number Everyone's Suddenly Talking About
Your wearable just started showing a VO2 max number, and it's suddenly being treated like a hidden vital sign. Here's what it actually measures, why it's become a longevity metric, and how accurate the estimate really is.
What Resting Heart Rate Actually Predicts
Your wearable buzzes with a resting heart rate number every morning, glanced at and forgotten. Here's what it actually measures, what the research links it to, and why lower isn't always better.